Improvement of surface tension discrete model in the ISPH-FVM coupling method

Abstract

In the simulation of two-phase incompressible fluid involving surface tension, the approximate calculation of surface tension plays an important role in the accuracy of phase interface tracking and reproduction. The ISPH-FVM coupling method was proposed to simulate two-phase incompressible flow, which combines the advantages of the incompressible smoothed particle hydrodynamics (ISPH) in interface tracking and the finite volume method (FVM) in the calculation of flow field. In the original ISPH-FVM coupling method, the continuous surface force model (CSF) is used to estimate the surface tension between phase interfaces, which is discretized by smoothed particle approximation (ISPH-FVM-S). In the calculation of ISPH-FVM-S, the accuracy of surface tension method will be decreased through the direct particle interpolation when the interface changes complex. To improve the simulation accuracy of the ISPH-FVM coupling method, this paper proposes two improved discrete models for surface tension calculation, one is inspired by VOF method (ISPH-FVM-V) and the other is inspired by Level Set method (ISPH-FVM-L). Several benchmark cases are tested to illustrate the effectiveness of two improved surface tension discrete models. The results show that ISPH-FVM-V model and ISPH-FVM-L model have better accuracy and stability than ISPH-FVM-S in two-phase flow problems with complex interface topology changes. The work of this paper can further expand the application of ISPH-FVM coupling method in simulation of complex two-phase flow involving surface tension.